An outbreak of dysentery in a rural district of Zimbabwe: the role of personal hygiene at public gatherings.

OBJECTIVES

To characterize the nature and extent of the outbreak; to determine the risk factors associated with contracting shigellosis; and to institute disease control and preventive measures.

DESIGN

Case control study.

SETTING

Nyaure Ward, Goromonzi District, Mashonaland East Province, Zimbabwe.

SUBJECTS: 52 cases and 52 controls. A case was defined as any resident of Nyaure Ward who presented with bloody diarrhoea (three or more loose stools/day) between 25 July and 25 October 1997.

MAIN OUTCOME MEASURES: Frequencies of symptoms, types of treatment received, risk factors for contracting the illness.

RESULTS

The median age was 17 (Q1 = 8, Q3 = 30) years for cases and 19 (Q1 = 7, Q3 = 28) years for controls. Prominent symptoms were abdominal cramps (96.2%), malaise and fever (92.3%), nausea and vomiting (50.0%). The median duration of diarrhoea was 13 (Q1 = 6, Q3 = 14) days. Eighteen (34.6%) cases were admitted and of these five were referred to a central hospital and two of them complicated with haemolytic uraemic syndrome. The case fatality rate was 1.6%. Twenty four(46.1%) of the cases had Shigella dysenteriae type I, sensitive to Nalidixic acid, Kanamycin, and Doxycycline but resistant to Metronidazole, isolated from the stool specimen. Water samples did not yield any pathogens. Significant risk factors associated with contracting dysentery were shared hand washing in the same standing water at gatherings[OR = 8.47, 95% CI: (2.43-31.33)] or within homes[OR = 60.43, 95% CI: (15.73 to 256.00)]. The use of Blair toilets was a protective factor[OR = 0.03, 95% CI: (0.01 to 0.11)].

CONCLUSION

The epidemiologic evidence implicated contamination of water used for shared hand washing before meals as the source of the infection. The common practice of shared hand washing in standing water should be discouraged at all gatherings and within households to avoid future outbreaks.